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Cof Cymru: National Historic Assets of Wales · Wales

Eureka Slate Mill

Llanllyfni, Gwynedd, Wales

The record

Designation
Listed building, Grade II
Broad class
Industrial
Date of designation
21 July 2000
Locality
Pen-yr-Orsedd
Town
Caernarfon
Community
Llanllyfni
Unitary authority
Gwynedd
Country
Wales
Coordinates
53.06252, -4.22622
Cadw reference
23675

Slide toward Today to fade the historical sheet and see the modern map underneath.

David Rumsey Map Collection, Stanford Libraries

Shown on 5 historical map sheets, the earliest the 1795 "To Sir Watkin Williams-Wynn Bart ... the map of the six counties of North Wales is most humbly inscribed by his obedient humble servant" (Llyfrgell Genedlaethol Cymru – The National Library of Wales).

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This record in Cadw's own full report ↗

Cadw's description

Located on Level VIII (Bonc Brig) of Pen- yr-Orsedd Slate Quarry immediately to the north-east of the slate steps leading down to Level VI (Bonc yr Offis).

Known as the Eureka mill, the building was constructed in 1896 and originally powered by a steam engine; substantially remodelled to house diamond saws in the 1960s and again in 1978-9 to admit road vehicles. The quarry opened c1816 and in 1863 it was bought by W A Darbishire & Co. During the 1890s about 450 men worked here: it finally closed in 1997.

Regularly coursed slate slabs and rubblestone; half-hipped slate roofs with full-length skylighting to ridges on original building, now extended down the roofslopes in corrugated plastic sheeting. Original plan comprises 2 long rectangular ranges aligned south-east to north-west with central valley; lower gabled ranges to north-west may also be original or added shortly afterwards. Both main ranges were originally accessed by railways in the end walls, while the long north-east wall has a doorway inserted into it to admit tracked vehicles. A large breeze block and metal-sheet roofed building (c1978) has been added to the north-east side linking the building to a small late C19 stone structure with a lean-to slate slab roof.

Original king-post roof structure to C19 building. Contains late C20 Anderson Grice saws and a slate dresser. A conveyor belt has been installed in the south-east gable to take out trimming waste.

Included as a substantial slate mill at the centre of the Pen-yr-Orsedd Slate Quarry, which despite extensive modification retains its basic original form.

Nearby in the register

Other entries of the same register within about three miles of this one, by straight line.

Designated Historic Asset GIS Data, The Welsh Historic Environment Service (Cadw), 2026-09-07, licensed under the Open Government Licence http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Cadw, the Welsh Historic Environment Service · Open Government Licence v3.0
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